Fuel oil



Patented Sept. 15, 1936 UNITED STATES PATENT OFFICE FUEL OIL No, Drawing. Application June 14, 1933, Serial No. 675,710. In Great Britain June 15, 1932 5 Claims. (Cl. 44-9) This invention relates to fuel oil and to primers therefor which are added to the fuel oil for the purpose of lowering its spontaneous ignition temperature and/or accelerating its combustion. Fuel -oil containing such primers is used chiefly in connection with internal combustion engines of the so-called Diesel type inwhich ignition of the fuel is effected by the heat developed in the compression of the air and it has been previously proposed to add to fuel oil for such engines a small percentage of a primer which explodes when rapidly heated, the temperature at which it explodes being lower than the spontaneous ignition temperature of the fuel oil itself. The beneficial action of such primers for shortening the period between the injection of the fuel oil and its ignition, and in eliminating bumping, has already been pointed out by previous workers.

I have now found that excellent primers for fuel oil are provided by oxygenated organic compounds of copper, e. g., copper salts of organic acids such as copper oleate, or the copper compound of acetyl acetone or of propionyl acetone, which are non-explosive in character and therefore more suitable for commercial use. These substances may be added to the oil in concentrations up to about 10%, but preferably smaller amounts of the order of 1-'5% are used.

My primers are also valuable as additions to oils containing large quantities of aromatic bodies, which are characterized by high spontaneous ignition temperatures. I can thus use oils obtained by the destructive distillation or hydrogenation of coal or the like, which have hitherto been of little or no value as fuel oil for internal combustion engines.

Thus an oil fraction boiling up to 300 C., ob-

tained by the destructive hydrogenation of coal,

0.5% to 5.0% by weight of the resulting mixture.

was tested in a Moore apparatus and found to have a spontaneous ignition temperature of 400 C., the delay period between injection and ignition at this temperature being three seconds. By adding 2% of copper oleate to the oil the spontaneous ignition temperature was reduced to 355 C. and the delay period to 1.9 seconds. By adding 1% of the copper compound of propionyl acetone to another sample of the oil, the spontaneous ignition temperature was reduced to 365 C. and the delay period to 2.2 seconds- Certain of the substances which it has been suggested to add as primers lower the ignition. temperature of the oil but have a relatively small effect on the' delay period, whilst with other substances the delay period is reduced but the ignition temperature is not lowered to the desired extent. In one of its forms the invention contemplates the addition of two or more primers to the fuel oil, one of which is selected to lower the ignition temperature and another of which is selected to reduce the delay period. Thus, I may 5 add to a fuel oil of the Diesel type, for example middle oil produced by the destructive hydrogenation of coal, an oxygenated copper compound or'- compounds and an alkyl nitrate or nitrite.

For example, I may add to a middle oil produced 10 by-the destructive hydrogenation of coal, which oil was initially a spontaneous ignition temperature of 395 C., and a delay period of 2.8 seconds at 400 C. (measured in an experimental apparatus of the Moore typel 0.5% by weight of ethyl 1 onds, whilst 2% of copper oleate when added alone to the oil, reduces the spontaneous ignition temperature to 355 C., and the delay period at 400 C. to 1.9 seconds.

The above description and speciflcexamples are illustrative only. Any variation therefrom or modification thereof which conforms to the spirit of the invention is included within the scope of the claims.

I claim: r

1. A compression ignition fuel comprising a high boiling fuel oil of the type used as fuel for Diesel engines and two separate compounds, one ethyl nitrateand the other. an oxygenated organic compound of copper, each of said compounds being present in amounts of the order of 2. A compression ignition fuel comprising a high boiling heavy oil of the type used as fuel for Diesel engines, ethyl nitrate, and an oxygenated compound of copper, said compound being taken from the class consisting of copper oleate, copper acetyl acetone and copper propionyl acetone, each of said compounds being present in amounts of -the order of 0.5% to 5.0% by weight of the resulting mixture.

3. A compression. ignition fuel comprising a high boiling heavy ;oi1 of the type used as fuel v for Diesel enginesjethyl nitrate and copper oleate, said ethyl nitrate and copper oleate being present in amounts of the orderof 0.5% to 5.0% by weight of the resulting mixture.

4. A process of modifying a middle oil obtained by the destructive hydrogenation of coal so that it may be used as a compression ignition Iuel which comprises addingto said oil ethyl nitrate and a. compound of the group consisting of copper oleate, copper acetyl acetone and copper propionyl acetone, each oi. these compoundsbeing added in amounts of the order of 0.5% to 5.0% by weight of the resulting mixture.

5. A process of modifying a middleoil obtained by the destructive hydrogenation of coal so that 'it may be used as a compression ignition fuel which comprises adding to said oil ethyi'nitratc and copper oleate, each of these ingredients be ing added in amounts of'the order of 0.5%- to 5.0% by weight of the resulting mixture.

' DONALD ALBERT HOWE. v 

